[Sean]

The FM antenna on my 42-1015 is indeed a dipole. It is not a continuous wire and there is a gap of a few inches between the ends of each wire at the bottom of the cabinet. For what it's worth, mine has cloth insulated wire instead of rubber insulation.

To answer your 2nd question, I think a mechanical (and you also mention electrical) background really helps in learning how to fix old radios. It means that you can learn and understand things of a technical nature. There are many knowledgeable people on this forum that can help you along. You have probably already read some warnings but I do also want to mention that you need to be careful when working on any vacuum tube equipment due to the high voltages present.